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cpuidle: create bootparam "cpuidle.off=1" 

useful for disabling cpuidle to fall back
to architecture-default idle loop

cpuidle drivers and governors will fail to register.
on x86 they'll say so:

intel_idle: intel_idle yielding to (null)
ACPI: acpi_idle yielding to (null)

Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Len Brown 2011-04-01 18:13:10 -04:00
parent 6dccf9c508
commit 62027aea23
5 changed files with 20 additions and 0 deletions
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3
Documentation/kernel-parameters.txt
View File

@ -546,6 +546,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
/proc/<pid>/coredump_filter. /proc/<pid>/coredump_filter.
See also Documentation/filesystems/proc.txt. See also Documentation/filesystems/proc.txt.
cpuidle.off=1 [CPU_IDLE]
disable the cpuidle sub-system
cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Format: Format:
<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]

10
drivers/cpuidle/cpuidle.c
View File

@ -28,6 +28,12 @@ LIST_HEAD(cpuidle_detected_devices);
static void (*pm_idle_old)(void); static void (*pm_idle_old)(void);
static int enabled_devices; static int enabled_devices;
static int off __read_mostly;
int cpuidle_disabled(void)
{
return off;
}
#if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT) #if defined(CONFIG_ARCH_HAS_CPU_IDLE_WAIT)
static void cpuidle_kick_cpus(void) static void cpuidle_kick_cpus(void)
@ -427,6 +433,9 @@ static int __init cpuidle_init(void)
{ {
int ret; int ret;
if (cpuidle_disabled())
return -ENODEV;
pm_idle_old = pm_idle; pm_idle_old = pm_idle;
ret = cpuidle_add_class_sysfs(&cpu_sysdev_class); ret = cpuidle_add_class_sysfs(&cpu_sysdev_class);
@ -438,4 +447,5 @@ static int __init cpuidle_init(void)
return 0; return 0;
} }
module_param(off, int, 0444);
core_initcall(cpuidle_init); core_initcall(cpuidle_init);

1
drivers/cpuidle/cpuidle.h
View File

@ -13,6 +13,7 @@ extern struct list_head cpuidle_governors;
extern struct list_head cpuidle_detected_devices; extern struct list_head cpuidle_detected_devices;
extern struct mutex cpuidle_lock; extern struct mutex cpuidle_lock;
extern spinlock_t cpuidle_driver_lock; extern spinlock_t cpuidle_driver_lock;
extern int cpuidle_disabled(void);
/* idle loop */ /* idle loop */
extern void cpuidle_install_idle_handler(void); extern void cpuidle_install_idle_handler(void);

3
drivers/cpuidle/driver.c
View File

@ -26,6 +26,9 @@ int cpuidle_register_driver(struct cpuidle_driver *drv)
if (!drv) if (!drv)
return -EINVAL; return -EINVAL;
if (cpuidle_disabled())
return -ENODEV;
spin_lock(&cpuidle_driver_lock); spin_lock(&cpuidle_driver_lock);
if (cpuidle_curr_driver) { if (cpuidle_curr_driver) {
spin_unlock(&cpuidle_driver_lock); spin_unlock(&cpuidle_driver_lock);

3
drivers/cpuidle/governor.c
View File

@ -81,6 +81,9 @@ int cpuidle_register_governor(struct cpuidle_governor *gov)
if (!gov || !gov->select) if (!gov || !gov->select)
return -EINVAL; return -EINVAL;
if (cpuidle_disabled())
return -ENODEV;
mutex_lock(&cpuidle_lock); mutex_lock(&cpuidle_lock);
if (__cpuidle_find_governor(gov->name) == NULL) { if (__cpuidle_find_governor(gov->name) == NULL) {
ret = 0; ret = 0;